North Goonyella project costs of US$28.4 million came in below the June quarterly guidance range of $30 million to $35 million, even with $2.3 million in charges associated with the voluntary employee reduction program, based on reduced activity levels at the mine.

Peabody CEO Glenn Kellow told an analysts' briefing the company was seeking to contain costs as the ongoing investigation of the fire incident and re-entry of the mine continued.

"I think we'd expect the voluntary reduction program, which had about 20 people participate in that program, to have a relatively quick payback on that activity," he said.

"We'd expect to rehire when … appropriate as we continue to re-phase production. But at this point in time, we want to make sure that we are appropriately matching our expenses with the level of work required as we progress along the path."

Peabody is continuing to work to appropriately scale on-site activities and is evaluating prospective paths forward.

"The North Goonyella project team is assessing prospective paths, timetables and costs to maximise value," the company said.

"The company continues to take action to appropriately scale on-site activities based on underground mine conditions and external factors, with all work currently being undertaken required to preserve value. 

"Actions include the completion of a voluntary reduction program; continued engagement with the Queensland Mines Inspectorate on the evolving recovery protocols; and conducting extensive value-engineering activities on prospective paths."